Europe and most other countries in the world use a voltage which is twice that of the US. It is between 220 and 240 volts, whereas in Japan and in most of the Americas the voltage is between 100and 127 volts.

The system of three-phase alternating current electrical generation and distribution was invented by a nineteenth century creative genius named Nicola Tesla who preferred 240 volts AC, which put himat odds with Thomas Edison, whose direct current (DC) systems were 110 volts. Edison had athe safety factor of the lower voltage, but DC couldn't provide the power to a distance that AC could.

When the German company AEG built the first European generating facility, its engineers decided to fix the frequency at 50 Hz, because the number 60 didn't fit the metric standard unit sequence. At that time, AEG had a virtual monopoly and their standard spread to the rest of the continent.

In Britain, differing frequencies proliferated, and only after World War II the 50-cycle standard was established. A mistake, however.

Not only is 50 Hz 20% less effective in generation, it is 10-15% less efficient in transmission, it requires up to 30% larger windings and magnetic core materials in transformer construction. Electric motors are much less efficient at the lower frequency, and must also be made more robust to handle the electrical losses and the extra heat generated.

Today, only a handful of countries (Antigua, Guyana, Peru, the Philippines, South Korea and the Leeward Islands) follow Tesla’s advice and use the 60 Hz frequency together with a voltage of 220-240 V.

Originally Europe was 120 V too, but it was been deemed necessary to increase voltage to get more power with less losses and voltage drop from the same copper wire diameter.

The US also wanted to change but because of the cost involved to replace all electric appliances, they decided not to. At the time (50s-60s) the average US household already had a fridge, a washing-machine, etc..., but not in Europe.

The end result is that now, the US seems not to have evolved from the 50s and 60s, and still copes with problems as light bulbs that burn out rather quickly when they are close to the transformer (too high a voltage), or just the other way round: not enough voltage at the end of the line (105 to 127 volt spread !).